Conventional turbochargers often include controllable features such as a variable geometry turbine or an exhaust wastegate that exist in a high temperature environment (e.g., possibly in excess of 1000 degrees Fahrenheit or 538 degrees Celsius). To control such features, a shaft is typically positioned in a bore of a housing where one end of the shaft is exposed to an environment with a high operational temperature while the other end of the shaft is exposed to an environment with a lower operational temperature. The temperature differential complicates sealing the shaft in the bore. Specifically, where one side of the shaft is exposed to exhaust gas, leakage of exhaust gas is a commonly occurring problem.
Various exemplary techniques described herein can reduce gas leakage around a control component, such as a shaft, for controlling a feature that exists at least partially in a high temperature environment.